Fix: empty Enter on VM selection crashes due to set -u (unset variable)

Added || true on read and ${:-} default expansion to handle empty input safely.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pharmq-setup.sh

@@ -435,10 +435,10 @@ PYEOF
         print_ok "VM 백업 자동 선택: $TEMPLATE_VMID"
     else
         echo -ne "${CYAN}복원할 VM 백업 ID (숫자, Enter로 건너뛰기): ${NC}"
-        read -r TEMPLATE_VMID </dev/tty
+        read -r TEMPLATE_VMID </dev/tty || true
     fi
 
-    if [ -z "$TEMPLATE_VMID" ]; then
+    if [ -z "${TEMPLATE_VMID:-}" ]; then
         print_warn "VM 복원을 건너뜁니다."
         VM_VMID=""
         print_ok "Phase 4 완료: PBS 등록됨 (VM 복원 스킵)"